Further theme system developments

app/App/Providers/ThemeServiceProvider.php

@@ -4,6 +4,8 @@
 
 use BookStack\Theming\ThemeEvents;
 use BookStack\Theming\ThemeService;
+use BookStack\Theming\ThemeViews;
+use Illuminate\Support\Facades\Blade;
 use Illuminate\Support\ServiceProvider;
 
 class ThemeServiceProvider extends ServiceProvider
@@ -24,7 +26,22 @@ public function boot(): void
     {
         // Boot up the theme system
         $themeService = $this->app->make(ThemeService::class);
+        $viewFactory = $this->app->make('view');
+        if (!$themeService->getTheme()) {
+            return;
+        }
+
         $themeService->readThemeActions();
         $themeService->dispatch(ThemeEvents::APP_BOOT, $this->app);
+
+        $themeViews = new ThemeViews();
+        $themeService->dispatch(ThemeEvents::THEME_REGISTER_VIEWS, $themeViews);
+        $themeViews->registerViewPathsForTheme($viewFactory->getFinder());
+        if ($themeViews->hasRegisteredViews()) {
+            $viewFactory->share('__themeViews', $themeViews);
+            Blade::directive('include', function ($expression) {
+                return "<?php echo \$__themeViews->handleViewInclude({$expression}, array_diff_key(get_defined_vars(), ['__data' => 1, '__path' => 1])); ?>";
+            });
+        }
     }
 }

app/App/helpers.php

@@ -81,8 +81,7 @@ function setting(?string $key = null, mixed $default = null): mixed
 
 /**
  * Get a path to a theme resource.
- * Returns null if a theme is not configured and
- * therefore a full path is not available for use.
+ * Returns null if a theme is not configured, and therefore a full path is not available for use.
  */
 function theme_path(string $path = ''): ?string
 {

app/Config/view.php

@@ -8,12 +8,6 @@
  * Do not edit this file unless you're happy to maintain any changes yourself.
  */
 
-// Join up possible view locations
-$viewPaths = [realpath(base_path('resources/views'))];
-if ($theme = env('APP_THEME', false)) {
-    array_unshift($viewPaths, base_path('themes/' . $theme));
-}
-
 return [
 
     // App theme
@@ -26,7 +20,7 @@
     // Most templating systems load templates from disk. Here you may specify
     // an array of paths that should be checked for your views. Of course
     // the usual Laravel view path has already been registered for you.
-    'paths' => $viewPaths,
+    'paths' => [realpath(base_path('resources/views'))],
 
     // Compiled View Path
     // This option determines where all the compiled Blade templates will be

app/Theming/ThemeEvents.php

@@ -134,6 +134,16 @@ class ThemeEvents
      */
     const ROUTES_REGISTER_WEB_AUTH = 'routes_register_web_auth';
 
+
+    /**
+     * Theme register views event.
+     * Called by the theme system when a theme is active, so that custom view templates can be registered
+     * to be rendered in addition to existing app views.
+     *
+     * @param \BookStack\Theming\ThemeViews $themeViews
+     */
+    const THEME_REGISTER_VIEWS = 'theme_register_views';
+
     /**
      * Web before middleware action.
      * Runs before the request is handled but after all other middleware apart from those

app/Theming/ThemeService.php

@@ -6,6 +6,7 @@
 use BookStack\Exceptions\ThemeException;
 use Illuminate\Console\Application;
 use Illuminate\Console\Application as Artisan;
+use Illuminate\View\FileViewFinder;
 use Symfony\Component\Console\Command\Command;
 
 class ThemeService
@@ -81,12 +82,14 @@ public function registerCommand(Command $command): void
     public function readThemeActions(): void
     {
         $themeActionsFile = theme_path('functions.php');
-        if ($themeActionsFile && file_exists($themeActionsFile)) {
-            try {
-                require $themeActionsFile;
-            } catch (\Error $exception) {
-                throw new ThemeException("Failed loading theme functions file at \"{$themeActionsFile}\" with error: {$exception->getMessage()}");
-            }
+        if (!$themeActionsFile || !file_exists($themeActionsFile)) {
+            return;
+        }
+
+        try {
+            require $themeActionsFile;
+        } catch (\Error $exception) {
+            throw new ThemeException("Failed loading theme functions file at \"{$themeActionsFile}\" with error: {$exception->getMessage()}");
         }
     }
 

app/Theming/ThemeViews.php

@@ -0,0 +1,96 @@
+<?php
+
+namespace BookStack\Theming;
+
+use BookStack\Exceptions\ThemeException;
+use Illuminate\View\FileViewFinder;
+
+class ThemeViews
+{
+    /**
+     * @var array<string, array<string, int>>
+     */
+    protected array $beforeViews = [];
+
+    /**
+     * @var array<string, array<string, int>>
+     */
+    protected array $afterViews = [];
+
+    /**
+     * Register any extra paths for where we may expect views to be located
+     * with the provided FileViewFinder, to make custom views available for use.
+     */
+    public function registerViewPathsForTheme(FileViewFinder $finder): void
+    {
+        $finder->prependLocation(theme_path());
+    }
+
+    /**
+     * Provide the response for a blade template view include.
+     */
+    public function handleViewInclude(string $viewPath, array $data = []): string
+    {
+        if (!$this->hasRegisteredViews()) {
+            return view()->make($viewPath, $data)->render();
+        }
+
+        $viewsContent = [
+            ...$this->renderViewSets($this->beforeViews[$viewPath] ?? [], $data),
+            view()->make($viewPath, $data)->render(),
+            ...$this->renderViewSets($this->afterViews[$viewPath] ?? [], $data),
+        ];
+
+        return implode("\n", $viewsContent);
+    }
+
+    /**
+     * Register a custom view to be rendered before the given target view is included in the template system.
+     */
+    public function renderBefore(string $targetView, string $localView, int $priority = 50): void
+    {
+        $this->registerAdjacentView($this->beforeViews, $targetView, $localView, $priority);
+    }
+
+    /**
+     * Register a custom view to be rendered after the given target view is included in the template system.
+     */
+    public function renderAfter(string $targetView, string $localView, int $priority = 50): void
+    {
+        $this->registerAdjacentView($this->afterViews, $targetView, $localView, $priority);
+    }
+
+    public function hasRegisteredViews(): bool
+    {
+        return !empty($this->beforeViews) && !empty($this->afterViews);
+    }
+
+    protected function registerAdjacentView(array &$location, string $targetView, string $localView, int $priority = 50): void
+    {
+        $viewPath = theme_path($localView . '.blade.php');
+        if (!file_exists($viewPath)) {
+            throw new ThemeException("Expected registered view file at \"{$viewPath}\" does not exist");
+        }
+
+        if (!isset($location[$targetView])) {
+            $location[$targetView] = [];
+        }
+        $location[$targetView][$viewPath] = $priority;
+    }
+
+    /**
+     * @param array<string, int> $viewSet
+     * @return string[]
+     */
+    protected function renderViewSets(array $viewSet, array $data): array
+    {
+        $paths = array_keys($viewSet);
+        usort($paths, function (string $a, string $b) use ($viewSet) {
+            return $viewSet[$a] <=> $viewSet[$b];
+        });
+
+        return array_map(function (string $viewPath) use ($data) {
+            return view()->file($viewPath, $data)->render();
+        }, $paths);
+    }
+}

tests/ThemeTest.php

@@ -492,6 +492,45 @@ public function test_public_folder_contents_accessible_via_route()
         });
     }
 
+    public function test_theme_register_views_event_to_insert_views_before_and_after()
+    {
+        $this->usingThemeFolder(function (string $folder) {
+            $before = 'this-is-my-before-header-string';
+            $afterA = 'this-is-my-after-header-string-a';
+            $afterB = 'this-is-my-after-header-string-b';
+            $afterC = 'this-is-my-after-header-string-{{ 1+51 }}';
+
+            $functionsContent = <<<'CONTENT'
+<?php use BookStack\Facades\Theme;
+use BookStack\Theming\ThemeEvents;
+use BookStack\Theming\ThemeViews;
+Theme::listen(ThemeEvents::THEME_REGISTER_VIEWS, function (ThemeViews $themeViews) {
+    $themeViews->renderBefore('layouts.parts.header', 'before', 4);
+    $themeViews->renderAfter('layouts.parts.header', 'after-a', 4);
+    $themeViews->renderAfter('layouts.parts.header', 'after-b', 1);
+    $themeViews->renderAfter('layouts.parts.header', 'after-c', 12);
+});
+CONTENT;
+
+            $viewDir = theme_path();
+            file_put_contents($viewDir . '/functions.php', $functionsContent);
+            file_put_contents($viewDir . '/before.blade.php', $before);
+            file_put_contents($viewDir . '/after-a.blade.php', $afterA);
+            file_put_contents($viewDir . '/after-b.blade.php', $afterB);
+            file_put_contents($viewDir . '/after-c.blade.php', $afterC);
+
+            $this->refreshApplication();
+            $this->artisan('view:clear');
+
+            $resp = $this->get('/login');
+            $resp->assertSee($before);
+            // Ensure ordering of the multiple after views
+            $resp->assertSee($afterB . "\n" . $afterA . "\nthis-is-my-after-header-string-52");
+        });
+
+        $this->artisan('view:clear');
+    }
+
     protected function usingThemeFolder(callable $callback)
     {
         // Create a folder and configure a theme